Ghasemikhah R, Sharbatkhori M, Mobedi I, Kia Eb, Harandi M Fasihi, Mirhendi H
Vali-e-asr Hospital, Arak University of Medical Sciences, Arak, Iran ; Department of Medical Parasitology & Mycology, School of Public Health; National Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran.
Iran J Parasitol. 2012;7(2):40-6.
Infectivity of herbivores with Trichostrongylus nematodes is widespread in many countries, having a major economic impact on breeding, survivability, and productivity of domestic livestock. This study was carried out on Trichostrongylus species isolated from domestic livestock in order to develop an easy-to-perform method for species identification.
Trichostrongylus isolates were collected from sheep, goat, cattle, and buffaloes in Khuzestan Province, southwest Iran. Primary species identification was carried out based on morphological characterization of male worms. PCR amplification of ITS2-rDNA region was performed on genomic DNA and the products were sequenced. Phylogenetic analysis of the nucleotide sequence data was conducted employing Bayesian Inference approach. Consequently, a restriction fragment length polymorphism (RFLP) profile was designed to differentiate Trichostrongylus species.
A consensus sequence of 238 nucleotides was deposited in the GenBank for Iranian isolates of Trichostrongylus species including T. colubriformis, T. capricola, T. probolurus and T. vitrinus. The designated RFLP using restriction enzyme TasI could readily differentiate among species having different ITS2 sequence. The molecular analysis was in concordance with morphological findings.
Phylogenetic analysis indicated a close relationship among the sequences obtained in this study and reference sequence of relevant species. ITS2-RFLP with TasI is recommended for molecular differentiation of common Trichostrongylus species.
食草动物感染毛圆线虫在许多国家都很普遍，对家畜的繁殖、生存能力和生产力产生重大经济影响。本研究对从家畜中分离出的毛圆线虫物种进行，以开发一种易于操作的物种鉴定方法。
从伊朗西南部胡齐斯坦省的绵羊、山羊、牛和水牛中收集毛圆线虫分离株。基于雄虫的形态特征进行初步物种鉴定。对基因组DNA进行ITS2-rDNA区域的PCR扩增，并对产物进行测序。采用贝叶斯推断方法对核苷酸序列数据进行系统发育分析。因此，设计了一种限制性片段长度多态性（RFLP）图谱来区分毛圆线虫物种。
包括蛇形毛圆线虫、山羊毛圆线虫、前翼毛圆线虫和透明毛圆线虫在内的伊朗毛圆线虫物种分离株的238个核苷酸的共有序列已存入GenBank。使用限制性内切酶TasI指定的RFLP可以很容易地区分具有不同ITS2序列的物种。分子分析与形态学结果一致。
系统发育分析表明，本研究获得的序列与相关物种的参考序列密切相关。建议使用TasI进行ITS2-RFLP分析以对常见毛圆线虫物种进行分子鉴别。
